--- src/libical/icaltz-util.c.orig	2022-10-17 20:53:57 UTC
+++ src/libical/icaltz-util.c
@@ -45,6 +45,11 @@
 #else
 #define bswap_32 swap32
 #endif
+#if defined(bswap64)
+#define bswap_64 bswap64
+#else
+#define bswap_64 swap64
+#endif
 #endif
 #endif
 #endif
